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Published on: 2/25/2026

Is it Colorectal Cancer? Why Your Gut is Changing & Medical Next Steps

Gut changes are common and often not cancer, but red flags like blood in the stool, bowel habit changes lasting more than 2 to 3 weeks, unexplained weight loss or fatigue, and persistent abdominal pain warrant prompt medical evaluation, and screening from age 45 can prevent cancer by finding and removing polyps.

There are several factors to consider, including benign causes, personal and family risk, and which tests to do next such as stool tests and colonoscopy; see below for the complete guidance and actionable next steps that may affect your care.

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Explanation

Is It Colorectal Cancer? Why Your Gut Is Changing & Medical Next Steps

Changes in your gut can be unsettling. Maybe your bowel habits have shifted. Maybe there's blood in your stool. Or perhaps you feel ongoing abdominal discomfort that just isn't going away.

It's natural to wonder: Is this colorectal cancer?

Colorectal cancer (also called colon cancer or rectal cancer) is one of the most common cancers worldwide. The good news is that when caught early, it is highly treatable. Many gut changes are caused by less serious conditions — but some symptoms should never be ignored.

Let's walk through what colorectal cancer is, what symptoms to watch for, why your gut may be changing, and what medical steps to take next.


What Is Colorectal Cancer?

Colorectal cancer begins in the colon or rectum, which are parts of the large intestine. Most cases start as small, noncancerous growths called polyps. Over time — often years — some polyps can turn into cancer.

This slow development is why screening is so powerful. Detecting and removing polyps early can prevent colorectal cancer entirely.


Common Symptoms of Colorectal Cancer

In early stages, colorectal cancer may not cause symptoms. That's why screening is so important.

When symptoms do appear, they may include:

  • A persistent change in bowel habits (diarrhea, constipation, or narrower stools)
  • Blood in the stool (bright red or dark/black)
  • Ongoing abdominal discomfort (cramps, gas, pain)
  • A feeling that the bowel doesn't empty completely
  • Unexplained weight loss
  • Weakness or fatigue (often due to anemia)
  • Rectal bleeding

It's important to understand that these symptoms do not automatically mean colorectal cancer. Conditions like hemorrhoids, irritable bowel syndrome (IBS), infections, inflammatory bowel disease (IBD), and diverticulosis can cause similar symptoms.

However, persistent or worsening symptoms deserve medical evaluation.


Why Is My Gut Changing?

Not every bowel change is cancer. In fact, most are not. Common reasons for gut changes include:

1. Diet Changes

  • Increased or decreased fiber
  • More processed foods
  • New food intolerances
  • Dehydration

2. Stress

Stress can alter gut motility and trigger constipation or diarrhea.

3. Medications

Antibiotics, iron supplements, pain medications, and some antidepressants can affect bowel habits.

4. Infections

Bacterial or viral infections can temporarily disrupt digestion.

5. Benign Conditions

  • Hemorrhoids (can cause bleeding)
  • Anal fissures
  • IBS
  • IBD (Crohn's disease, ulcerative colitis)
  • Polyps (which may or may not become cancerous)

Still, if symptoms are new, persistent (more than a few weeks), or worsening, colorectal cancer must be ruled out.


Who Is at Higher Risk for Colorectal Cancer?

Anyone can develop colorectal cancer, but risk increases with:

  • Age over 45
  • Family history of colorectal cancer or polyps
  • Personal history of polyps
  • Inflammatory bowel disease
  • Obesity
  • Smoking
  • Heavy alcohol use
  • Sedentary lifestyle
  • Diet high in processed or red meat

If you have a first-degree relative (parent, sibling, child) with colorectal cancer, your risk is significantly higher.


When Should You Be Concerned?

You should seek medical evaluation promptly if you experience:

  • Blood in your stool (especially repeatedly)
  • Black or tarry stools
  • Unexplained iron-deficiency anemia
  • Unintentional weight loss
  • Persistent abdominal pain
  • Ongoing bowel habit changes lasting more than 2–3 weeks

These do not guarantee colorectal cancer — but they require proper testing.


Medical Next Steps: What to Expect

If colorectal cancer is suspected, your doctor may recommend:

1. Physical Exam and Medical History

They will ask about:

  • Duration of symptoms
  • Family history
  • Diet and lifestyle
  • Medication use

2. Stool Tests

These can check for hidden (occult) blood in the stool.

3. Blood Tests

To look for:

  • Anemia
  • Signs of inflammation

4. Colonoscopy

This is the most important diagnostic tool. A flexible camera examines the colon and rectum. During the procedure:

  • Polyps can be removed
  • Suspicious areas can be biopsied

If colorectal cancer is found, early detection dramatically improves survival rates.


Screening: Even Without Symptoms

Most medical organizations recommend regular colorectal cancer screening starting at age 45 for average-risk adults.

Screening options include:

  • Colonoscopy (every 10 years if normal)
  • Stool-based tests (annually or every few years)
  • CT colonography (in certain cases)

If you have higher risk factors, screening may begin earlier.


What If It Is Colorectal Cancer?

Hearing a cancer diagnosis is frightening. But it's important to understand:

  • Early-stage colorectal cancer has a high survival rate.
  • Many cases are completely curable with surgery.
  • Treatments may include surgery, chemotherapy, radiation, or targeted therapy.
  • Outcomes have improved significantly over the past decades.

The stage at diagnosis makes a major difference — which is why early evaluation matters.


What You Can Do Right Now

If you're concerned about your symptoms and want to better understand whether they could be related to something serious, use this free Colon Cancer symptom checker to get a personalized assessment in minutes based on your specific symptoms.

This is not a diagnosis, but it can help you decide how urgently to seek care.


Reducing Your Risk of Colorectal Cancer

While not all cases are preventable, you can lower your risk by:

  • Eating a high-fiber diet (fruits, vegetables, whole grains)
  • Limiting red and processed meats
  • Exercising regularly
  • Maintaining a healthy weight
  • Avoiding smoking
  • Limiting alcohol intake
  • Keeping up with recommended screenings

Lifestyle changes not only reduce colorectal cancer risk but also improve overall gut health.


A Balanced Perspective

It's important not to panic over every digestive change. Our gut naturally fluctuates due to diet, stress, and normal biological variation.

But it's equally important not to ignore persistent warning signs.

Colorectal cancer often develops silently. When symptoms appear, they deserve attention.

If something feels different from your normal baseline — especially if it persists — trust that instinct and get it checked.


The Bottom Line

Gut changes are common. Most are caused by noncancerous conditions. However, colorectal cancer is common enough that ongoing or concerning symptoms must be evaluated.

Do not self-diagnose. Do not ignore persistent bleeding or bowel changes. And do not delay screening if you are 45 or older.

If you are experiencing:

  • Blood in your stool
  • Ongoing bowel changes
  • Unexplained fatigue or weight loss
  • Persistent abdominal pain

Speak to a doctor promptly. Some causes may be minor. Others, including colorectal cancer, can be life-threatening if ignored.

Early detection saves lives. If something doesn't feel right, take the next step today.

(References)

  • * Maida, C. M., Sferrazzo, S., Alaimo, B., Scalia, G., Alaimo, I., Bellanca, L., Cannova, S., Alaimo, G., & D'Alessandro, R. (2021). Change in bowel habit and rectal bleeding as red flags for colorectal cancer: a systematic review. *Journal of Clinical Medicine*, *10*(14), 3097.

  • * Dekker, E., Tanis, P. J., Vleugels, J. L. A., Kasi, P. M., & Wallace, M. B. (2023). Diagnosis and Management of Colorectal Cancer: An Updated Review. *JAMA*, *329*(3), 251–263.

  • * US Preventive Services Task Force, Davidson, K. W., Barry, M. J., Mangione, C. M., Cabana, L. S., Caughey, A. B., ... & Wong, J. B. (2021). Colorectal Cancer Screening: Updated Recommendations From the U.S. Preventive Services Task Force. *JAMA*, *325*(19), 1965–1975.

  • * Rawla, P., Sunkara, T., & Barsouk, A. (2022). Colorectal Cancer: Epidemiology, Risk Factors, and Clinical Presentation. *Medical Sciences (Basel, Switzerland)*, *10*(4), 184.

  • * Zhang, M., Ye, Y., Ma, K., Wang, Y., Zhang, W., Chen, S., Sun, Y., & Chen, G. (2023). New advances in the diagnosis of colorectal cancer. *Frontiers in Oncology*, *12*, 1074092.

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